If it's a SHTF deal then I'd have to suggest an AR with a free floating barrel. You're talkin at least semi-auto, high capacity mags, and plenty of mag pockets/pouches to choose from when it comes carrying ammo. Pick a caliber ... they've got it (for the most part). Perhaps something to seriously consider. Maybe even JUST a stripped AR lower (build it any time in the future).
I was seriously considering a bolt action and installing a larger mag well, but it just didn't seem like the best bang for the buck when it came to the thought the SHTF scenario.
OK ... done with the rant. Do they make stripper clips for your 336? Probably not.
If they do the I'd look for something similar to this: